What lists actually spawn ammo into the inventories of NPCs? I have noted there are seemingly 3 or so different types of ammo lists (Ammo, LootAmmo, and WithAmmo) - but I would like to try and toss more ammo onto NPCs.

I checked out the NPCs use ammo mod to get an idea (the more ammo version), and I altered the lists they did in a patch method to make it ork with my current list, but it still seems that NPCs are spawning with lower amounts of ammo than what I was expecting after having made my edits.

So, yea, that is my question I suppose, let me know if you can be of help, would appreciate it.

There are some variations, but usually the NPCs get a Leveled Item called "WithAmmo" (i.e. a weapon with ammo). If you go to Items->Leveled Items in GECK and filter on WithAmmo you'll find them.

NPCs do not consume ammunition. So even if they have a machine gun and only 1 round of the correct ammo type they will never run out. So you don't need to give NPCs more ammunition.

Companions are different. When an NPC is your companion they will consume ammunition the normal way. But if a companion is not hired (or fired) they don't consume ammunition, 1 round is enough for them too, just like other NPCs. (Companion NPCs also have their own non-playable weapons and magical ammo that never runs out, but that is a special case, and if they have a playable weapon and ammo they'll use whatever they think is best.)

If it's simply a case of you wanting more ammo to loot from bodies, then edit those "WithAmmo" leveled items and find out what their base Ammo Leveled items are, and edit those base ammo leveled items.

For example: WithAmmo10mmPistolLoot uses the base leveled items Ammo10mm and Ammo10mm75 so you need to edit those two base items and that is sufficient. The base items are also used in containers (including NPCs) on their own, so editing the base ammo lists is probably your best strategy.

To edit them all is a huge amount of work, you'll see when you find out how many ammo items there are. It could be done but it's work. If it's just certain ammo you are interested in you could edit only those particular ones and save yourself a lot of work.

P.S. If it is simply a case of wanting more ammo to loot, Level 8 and Luck 5 will allow you to get the Scounger perk which will more than double the amount of ammo you typically find when looting containers or bodies. You'll see exactly how that works if you look at those leveled lists in GECK.

Well, actually, I have already modified every weapon in my game so NPCs do use ammo, thus the need for this. Was funny to watch Sunny run out of ammo still hunting the Geckos, but that results in her death in the gunfight with a guarantee as she tries to punch it out.

I think the difference with ammo is only the number you get with each option.
the ammo list has only 1 of each, sometimes more for automatic weapons (I suppose). it is the only difference with the non levelled ammo.
the lootammo contains a 100% chance for a small fixed number and a random chance for the scrounger perk.
The withammo contains a 75 percent chance of a full magazine,a single ammo to be sure they have one, but not the scrounger random number.

If you edited the list in another mod be sure the calculate for each item in count is checked in the levelled list box. It will increase the number randomly generated.